'74 Sunn Concert Bass...pretty low volume till it hits 5 or so...

[kiehano]

Just seems odd.  Could it be a problem?  My other 150ish watt amps are "global annihilation" loud by the time they hit 2!

[phatt]

Hi,
   Maybe Read up on *Log and Linear* pots and learn how they can alter the percieved power.

If both amplifiers can deliver the same wattage then it may simply be a different pot used for Volume control and I doubt there is anything wrong.
This is a common quirk with different gear.
Phil.

[kiehano]

Kind of thought so.  My Beta Lead uses all linear pots.  I just wondered if all of these were the same.  With an amp that old you never know what may have been tinkered with!

[gbono]

I'm assuming you compare the other amps using the same speaker cabinet? Your Sunn should drive a 4 ohm system fine - don't try anything lower in impedance unless you like the smell of burning components. My guess is that you have a damaged output transistor or your bias has drifted (only adjustable on some of the black/silver faced versions).